WASHINGTON (AP)  Iraq's missiles remain a threat to U.S. forces and allies in the Persian Gulf, despite nearly a dozen years of American advances in anti-missile technology.

Two-thirds of the estimated $1.6 billion cost of the Arrow-2 missile project was financed by the United States.

AP

The few dozen longer-range Scud missiles Iraq may have wobble so much in flight that they make a difficult target for America's most advanced Patriot anti-missile systems. But Iraq has developed shorter-range missiles that can fly under or overwhelm U.S. missile defenses.

And the United States has fewer than 40 of its most advanced Patriots ready for use.

That means missiles could be among Saddam Hussein's most threatening weapons if the United States decides to wage war against Iraq. One of Iraq's targets could be Kuwait, which the United States wrested away from Saddam in 1991 and where U.S. troops are massing for a possible invasion.

"Part of what the Iraqis would want to do is cause massive casualties in Kuwait with a chemical attack," said military analyst John Pike of GlobalSecurity.org. "It could create some real dilemmas for the American commander if the Iraqis are firing missiles faster than the Patriot can shoot them down."

Iraq's main missile threat during the Gulf war was the Scud, a missile Iraq bought wholesale from the former Soviet Union and later modified to extend its range. Iraq is believed to have hidden enough missiles or parts to have up to two dozen Scuds left.

It fired about 90 Scuds during the Gulf War, with 43 landing in Saudi Arabia and 39 in Israel. The deadliest single incident for U.S. troops was a Scud attack on a barracks in Saudi Arabia that killed 28 soldiers and injured 98.

The Pentagon reported firing 47 Patriot missiles at incoming Scuds, at first claiming an 80% success rate. After the war, the military revised that success rate downward several times and a congressional report concluded that Patriots succeeded in downing only four Scuds.

Patriots didn't work in the deadly barracks attack, for example, because of a software glitch that made the tracking system inaccurate by more than 740 yards.

The United States has upgraded its Patriots — known as the Patriot Advanced Capability II Guidance Enhanced Missile, or PAC-II GEM — since then to include more accurate radar and other equipment. Those upgraded Patriots shot down Scud missiles in tests over the Pacific in 1997, said Lt. Col. Rick Lehner, a spokesman for the Pentagon's Missile Defense Agency.

One of the Patriot's biggest problems is that Scud missiles — particularly Iraq's — are so poorly made that they wobble wildly in flight, making them harder to hit. They are also incredibly inaccurate, with a target radius of at least 2 kilometers. The barracks strike was essentially a lucky hit.

The Patriot upgrades haven't solved the wobbly target problem, said Theodore Postol, a professor of science and national security at the Massachusetts Institute of Technology.

"I don't believe the upgrades I'm aware of are likely to dramatically change the Patriot's capability against the kinds of Scuds the Iraqis have," said Postol, a frequent critic of the military's missile defense program.

The Patriot's warhead also is often not powerful enough to completely destroy a missile, meaning the Scud warhead could fall to the ground intact.

The Pentagon has developed a totally new missile — called the PAC III — that has a much better chance of shooting down missiles like Scuds. Unlike the Patriot, which explodes near its target, the PAC III is designed to hit its target head-on. The PAC III also is more maneuverable and has better tracking and guidance systems.

But so far, only 38 PAC III missiles have been delivered to the Army for operational testing, Lehner said.

After the Gulf War, Israel teamed up with the United States to develop the Arrow anti-missile system. That rocket destroys incoming missiles when they are above the atmosphere and flying more smoothly, partially solving the Scud wobble problem.

The United States has two Scuds and plans to gather more data about the missiles by mounting them with sensors and test-firing them over the Pacific from Vandenburg Air Force Base in California, Lehner said. The Scuds — which will not carry live warheads — will be tested before the end of the year, Lehner said.

U.N. resolutions after the Gulf War required Iraq to destroy all of its Scuds and any other missiles with a range of more than 150 kilometers, or about 95 miles. Iraq is believed to have hidden up to two dozen Scuds, which have a range of up to 373 miles.

Iraq also has an unknown number of new, shorter-range missiles developed under those regulations, including the Al Samoud and Ababil-100 missiles. A CIA report on Iraq released this month says U.S. officials believe those missiles can fly farther than the 95-mile limit.

Even under the U.N. limit, Kuwait is well within range of the Samoud and Ababil missiles. Iraq could use them to launch conventional, chemical or biological attacks on U.S. troops massing in Kuwait or on Kuwaiti civilians.

The shorter-range missiles are harder for Patriot and other anti-missile systems to knock down, since they fly lower than Scuds.

Even if the shorter-range missiles were loaded with chemical or biological weapons, their small size and American defenses would minimize the damage to U.S. forces, Pike said, because U.S. forces have the vaccinations and protective gear to withstand a chemical or biological attack.

"It would slow down the U.S. military mobilization there, and run the risk of substantial Kuwaiti civilian casualties," Pike said. "But my assumption is that Al Samoud chemical attacks would be more in the category of annoying provocation than something that has the potential to decisively alter the course of the war."

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